The present invention relates to an improved level device and a method of calibrating a level vial, carried by such a level device on a level body, with respect to reference surfaces defined by the level body.
Carpenter's levels and similar devices have long been used to determine whether a surface is level, i.e., horizontal, or vertical. Such level devices typically incorporate one or more level vials that are precisely oriented with respect to reference surfaces defined by the body of the level device. The typical level vial used in such level devices comprises an outer, transparent shell of glass or plastic defining an elongated cavity that has a slightly curved upper surface which is higher at the center than at the ends. The cavity is filled with a fluid, such as for example water, and a small bubble of air that floats on top of the fluid. When the vial is horizontal, the bubble will be in the middle of the vial. Typically, a pair of reference marks or bands are provided on the outer surface of the vial to assist the observer in assessing the position of the bubble. Assuming that the vial is properly calibrated with respect to a reference surface of the level body, the position of the bubble provides an indication as to the orientation of the reference surface. If the direction of elongation of the level vial is parallel to the reference surface of the level, the level can be used to determine whether a surface against which the reference surface is placed is horizontal. Similarly, if the direction of elongation of the level vial is perpendicular to the reference surface of the level, the level can be used to determine whether the reference surface is vertical. Some prior art levels use three level vials oriented at right angles to provide orientation information simultaneously with respect to at least two axes.
It will be appreciated that it is important for a level vial in such a level device to be positioned precisely with respect to a reference surface. However, proper calibration of the level vial can be somewhat difficult to achieve, especially if the vial is to be calibrated with respect to two reference surfaces. Additionally, it is important that calibration be accomplished quickly and inexpensively.
Accordingly, it is seen that there is a need for an improved level device and for a method of calibrating a level vial in such a device.